1. Field of the Invention
This invention relates to the preparation of ammonium nitrate and more specifically to the preparation of ammonium nitrate by the reaction of ammonium chloride and nitrogen dioxide.
2. Description of the Prior Art
In the preparation of ammonium nitrate, processes such as disclosed in B. B. Vadil'ev, Ya. A. Ravdin and E. J. Luk'yanova, "Reaction Between Ammonium Chloride and Nitric Acid", J. Gen. Chem. (USSR) 7, 2913-18 (1937), 32 C.A. 4897 (1938) have been developed wherein nitric acid is reacted with ammonium chloride. However, those processes wherein the reaction is carried out with the use of nitric acid or in aqueous solution cause serious corrosion problems and necessitate the use of expensive corrosion-resistant equipment.
While, as in U.S. Pat. No. 1,965,400, it has been proposed to minimize the corrosion problems by carrying out the reactions under anhydrous or substantially anhydrous conditions, here again certain practical difficulties are presented. For example, if it be attempted to use nitrogen peroxide vapors which are passed over or through a solid particulate mass of ammonium chloride as in U.S Pat. No. 1,965,400, the reaction proceeds very slowly unless enough moisture is present to give rise to corrosion problems. Indeed, whether the ammonium chloride be disposed in a stationary, granular bed with the nitrogen oxides passed therethrough in gaseous form or the contact between the solid chloride and the gases is brought about by a fluidized solids technique, there is a strong tendency for the solid particles to stick together and form a solid mass long before the reaction is completed.
Moreover, processes which have been developed for the conversion of alkali metal and alkaline earth metal chlorides to the corresponding nitrates by reaction with nitrogen oxide are not readily adaptable to the production of ammonium nitrate due to the rapid decomposition which ammonium nitrate undergoes. Exemplary of such alkai metal/alkaline earth metal processes are those disclosed by U.S. Pat. Nos. 1,604,660; 1,658,519; 1,717,951; 1,875,014; 2,057,957; 2,916,353; 2,963,345; and 3,211,525. See also Ann. Phil. 9, 355 (1817); C. W. Whittaker, F. O. Lundstrom and A. R. Mevz, "Preparation of Potassium Nitrate from Solid Potassium Chloride and Nitrogen Peroxide," Ind. Eng. Chem. 23. 1410 (1931); J. W. Mellor, A Comprehensive Treatise on Inorganic and Theoretical Chemistry, Vol. VIII, Suppl. II, N, Part II, page 420 (1967); H. Tramm and H. Yelde, "Spontaneous Decomposition of Ammonium Nitrate Melts", Angew. Chem. 47, 782-3 (1934), C.A. 29, 699 (1935); B. Rozman, "Thermal Decomposition of Ammonium Nitrate in the Presence of Chlorides", Zhur. Neorg. Klum, 6, 783-5 (1961), C.A. 56, 3107 (1962); J. Van R. Smit," Chloride -- Catalyzed Destruction of Ammonium Nitrate in Nitric Acid Medium", Chemistry and Industry, 2018 (Dec. 5, 1964); "Synthetic Saltpeter Scores," Chem. Week 97, p. 35-38 (July 24, 1965); European Chemical News, p. 34 (Technical Week Section) (Jan. 26, 1968).